The proposed research involves several related lines of investigation. We plan to exploit the observation, confirmed in this laboratory, that chondrosarcomas produce a simpler proteoglycan than do normal cartilage cells. The intent is to characterize fully the keratan sulfate-like product produced by a transplantable mouse chondrosarcoma, the product produced by a rat chondrosarcoma which we plan to carry out a comparative metabolic study of the animal tumor and fetal or very young chick tibial cartilage. The in vivo biosynthesis experiments will involve the actual isolation and fractionation of the proteoglycan and individual evaluation of the metabolic incorporation of label into each of the fractions. Both the polysaccharide and the protein portions of the molecule will be studied using 35SO4 and 3H and 14C amino acids and sugars. It is hoped that substantial information will be obtained about both normal and malignant cartilage metabolism which might be exploited in therapy. The key aspect of this study would be complete and adequate fractionation of the products and comparison of the normal with the cancerous. As an integral part of the proposed work, we intend to continue the fractionation studies already underway in this laboratory to produce more useful fractionation methods and information about the fine structure of the proteoglycans of cartilage. In particular, we would continue the studies on the interactions of proteoglycan with protein and on the changes in density and conformation of proteoglycan as a function of the type of cation.